Atypical severe progressive perioral ulceration due to herpes simplex virus on the background of undiagnosed HIV/AIDS.

Perioral ulcerative plaques have a broad list of differential diagnoses. We describe an unusual presentation of chronic progressive perioral ulceration due to herpes simplex type (HSV)-1 on a background of undiagnosed human immunodeficiency virus infection with acquired immunodeficiency syndrome. Whilst chronic mucocutaneous HSV is an AIDS-defining condition with both HSV-1 and HSV-2 implicated, typical reported cases describe vesicular eruptions rather than perioral ulcerative plaques. This case highlights that common infections may present atypically in immunocompromised individuals and may be a clue to underlying systemic illness.